Do I Need SPF When I’m Driving?
You might not technically be going outside, but your skin doesn't quite see it that way. UV can pass through some glass, which means your skin can be exposed during your commute, at your desk by the window, and in any room with natural light, even if you never technically step foot outside.
The Two Types of UV Radiation (and Why Only One Gets Stopped by Glass)
UV radiation from the sun comes in two forms: UVB and UVA. UVB is the one that causes sunburn, and laminated windshields – the kind in the front of most cars – block a significant amount of both UVB and UVA, so the windshield is actually doing more work than most people give it credit for.
Side windows are a little different. Most are made from tempered glass, which filters UVB reasonably well but lets a much higher percentage of UVA through. And because side windows are the ones closest to your face during a drive, that distinction matters.
UVA reaches deeper layers of the skin than UVB and contributes to long-term skin changes over time. It's also present on overcast days and doesn't require direct sunlight to reach your skin.
Incidental Sun Exposure Adds Up
Dermatologists noticed a pattern years ago. People who drive frequently tend to show more visible skin changes on the side of their face closest to the window. In the U.S., that's typically the left side.
Say you’re driving thirty minutes a day, so 2.5 hours a week. Over a year, that's more than 100 hours of UV exposure reaching the same areas of your face, through the same window, at the same angle. Repeat that for a few years, and you start to understand why dermatologists want you to wear your SPF.
The car is the most obvious example, but it's not the only one. Your desk by the window, a table at a café, your living room with all its natural light. It can all add up.
All Day, Every Day SPF Covers Your Bases
The solution: Apply your SunDay SPF every morning and then reapply it every two hours. Do it for the commute, the window seat, the lunch walk. In mineral sunscreens, zinc oxide works by physically blocking UV rays at the surface of the skin. No absorption required, which means protection starts immediately.
The Bottom Line
Most sun damage doesn't happen on beach days; it happens during the drive to work, at the desk by the window, during the errand run.
Dermatologists recommend daily SPF because consistent protection for incidental exposure is far more effective than occasional protection at peak exposure. Incidental exposure can add up, but daily habits can also offset it.
If mineral SPF is already in your morning routine, you’re most of the way there – just remember to reapply. And if it isn't, your commute is a pretty good place to start!